ALSA: hda: check stream decoupled register state

Check stream decoupled register value with requested value
before decoupling/coupling the stream.

Signed-off-by: Jeeja KP <jeeja.kp@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@kernel.org>